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x86: move stack_canary into irq_stack

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Impact: x86_64 percpu area layout change, irq_stack now at the beginning

Now that the PDA is empty except for the stack canary, it can be removed.
The irqstack is moved to the start of the per-cpu section.  If the stack
protector is enabled, the canary overlaps the bottom 48 bytes of the irqstack.

tj: * updated subject
    * dropped asm relocation of irq_stack_ptr
    * updated comments a bit
    * rebased on top of stack canary changes

Signed-off-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
This commit is contained in:
Brian Gerst
2009-01-19 12:21:28 +09:00
committed by Tejun Heo
parent 8c7e58e690
commit 947e76cdc3
10 changed files with 46 additions and 62 deletions
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7
arch/x86/kernel/cpu/common.c
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@@ -881,12 +881,13 @@ __setup("clearcpuid=", setup_disablecpuid);
#ifdef CONFIG_X86_64
struct desc_ptr idt_descr = { 256 * 16 - 1, (unsigned long) idt_table };
DEFINE_PER_CPU_PAGE_ALIGNED(char[IRQ_STACK_SIZE], irq_stack);
DEFINE_PER_CPU_FIRST(union irq_stack_union,
irq_stack_union) __aligned(PAGE_SIZE);
#ifdef CONFIG_SMP
DEFINE_PER_CPU(char *, irq_stack_ptr); /* will be set during per cpu init */
#else
DEFINE_PER_CPU(char *, irq_stack_ptr) =
per_cpu_var(irq_stack) + IRQ_STACK_SIZE - 64;
per_cpu_var(irq_stack_union.irq_stack) + IRQ_STACK_SIZE - 64;
#endif
DEFINE_PER_CPU(unsigned long, kernel_stack) =
@@ -960,7 +961,7 @@ void __cpuinit cpu_init(void)
loadsegment(fs, 0);
loadsegment(gs, 0);
load_pda_offset(cpu);
load_gs_base(cpu);
#ifdef CONFIG_NUMA
if (cpu != 0 && percpu_read(node_number) == 0 &&